Drugs may be delivered to patients by a variety of methods including oral, intravenous, intramuscular, inhalation, topical, subcutaneous delivery or delivery directly or locally to the treatment site (e.g., intrathecally, intraspinally, intraarticularly, etc.). The method of delivery chosen depends, among other things, upon the condition being treated, desired therapeutic concentration of the drug to be achieved in the patient and the duration of drug concentration that must be maintained.
Recently, drug depots have been developed which allow a drug to be introduced or administered to sites beneath the skin of a patient (e.g., subcutaneously or intramuscularly) so that the drug is slowly released over a long period of time. Such drug depots allow the drug to be released from the depot in a relatively uniform dose over a time period. This method of administering drugs is becoming especially important and popular in modulating hormonal replacement or contraception.
Previously, drug depots and other types of implants have been inserted into the treatment site beneath the skin by use of a large bore trocar device, which is a two-piece device that includes a cannula and an obdurator. The large size of the trocar device requires an incision to be made through the skin at the site of implant of the drug depot using a separate instrument (e.g., scalpel). A cannula and obdurator are inserted together through the skin at the incision site. Next, the obdurator is withdrawn, leaving the cannula in place as a guide for inserting the drug depot. The drug depot is inserted through the cannula, and the obdurator is used to push the implant to the end of the cannula. The cannula and obdurator are then withdrawn completely, leaving the implant in place beneath the skin.
Typically, because of the large size of the trocar devices, their use is limited to subcutaneously delivery of the drug depot over a large area (e.g., 2-2.5 inches), with a typical drug depot in the order of 1½ inches long. Thus, the trocar device is not suitable for many treatment sites because it lacks precision and may cause additional trauma to the tissue surrounding the desired site of implant.
Other drug depot devices have been developed to simplify implanting the drug depots. These devices have a handle for one-handed implantation of the drug depot, a small needle containing the drug depot to be implanted and a rod positioned within the needle for pushing the drug depot out of the needle. Once the needle containing the drug depot has been inserted at the site of implant, a spring loaded trigger on the handle is activated which causes the needle to be automatically withdrawn by a spring leaving the implanted drug depot in place. Unfortunately, it is not possible to control the motion of the needle in these devices because the needle will automatically retract upon activation of the trigger. The complex spring loaded propelling system and trigger of these devices increase the chances that the device will jam and fail to eject the drug depot when required.
Conventional needle and syringe devices have been used to implant a drug solution or suspension to sites such as, for example, the epidural space. These devices typically utilize a syringe preloaded with the drug solution and an epidural needle. The needle is inserted through the skin, supraspinus ligament, intraspinus ligament, ligamentum flavum and then into the epidural space. The drug solution is delivered through the needle to the epidural space using the syringe plunger. Conventional needle and syringe devices often do not easily allow controlled and precision implant of the drug depot. If multiple drug depot implants are needed, these conventional needle and syringe devices often do not allow accurate placement of the implant in a manner to optimize location, accurate spacing, and drug distribution.
New drug depot devices are needed, which can easily allow accurate and precise implantation of a drug depot with minimal physical and psychological trauma to a patient. When implanting several drug depots, a drug depot device is needed that accurately and precisely allows placement of the drug depot in a manner to optimize location, accurate spacing, and drug distribution.